Can anyone tell me why I am not receiving the attachments with the emails?

HTML SCRIPT:
<td width="120"><div align="right" class="style7"><span class="style6">Attach Resume: </span></div></td>
<input type="hidden" name="MAX_FILE_SIZE" value="1000000">
<td colspan="3" valign="middle"><input name="attachment" type="file" id="resume"></td>

PHP SCRIPT:
// check for an attachment if there is a file upload it
if ($attachment_name) {
if ($attachment_size > 0) {
if (!$attachment_type) $attachment_type = "application/unknown";
$content .= "Attached File: ".$attachment_name."\n";
$fp = fopen($attachment, "r");
$attachment_chunk = fread($fp, filesize($attachment));
$attachment_chunk = base64_encode($attachment_chunk);
$attachment_chunk = chunk_split($attachment_chunk);
}
}